In multi cylinder engines powered by a gaseous fuel, such as, for example, natural gas, the natural gas may be injected into a cylinder port through a gas nozzle prior to the combustion thereof. However, during the operation of the engine, due to sealing limitations between the gas nozzle and the engine, the natural gas may leak into different components of the engine.
For example, the leaked natural gas may flow from one of the cylinders to adjacent cylinders. In another example, the leaked natural gas may flow into an intake air passage and may mix with a flow of intake air therein. As a result, high variation in mass flow and concentration of the natural gas may be present between the different ports of the subsequent cylinders. Generally, maximum loss of natural gas due to leakage may take place at the cylinders located relatively closer to an inlet of the intake air as compared to that of the cylinders located further away from the inlet, due to decrease in velocity along the flow path. The leakage of the natural gas may result in inadequacy and variation in power delivery by the individual cylinders of the engine based on the quantity of loss of the natural gas.
U.S. Pat. No. 6,725,822 describes an intake air dispensing box for an engine. The dispensing box includes a body having an intake air inlet, first and second intake branch pipes and one of halves of a partition wall. The partition wall has an opening provided in its outer wall opposite from the first and second intake branch pipes to extend between first and second dispensing chambers, and a lid detachably coupled to the body to close the opening. The other half of the partition wall includes a valve bore and bearing bores.